Lead-bond type chip package and manufacturing method thereof

ABSTRACT

A lead-bond type chip package includes a multilayer substrate for supporting and electrical interconnecting a semiconductor chip. The multilayer substrate has a slot defined therein. The multilayer substrate comprises an interlayer circuit board having prepregs disposed thereon, a plurality of leads on the prepreg on the upper surface of the interlayer circuit board, and a plurality of solder pads for making external electrical connection on the prepreg on the lower surface of the interlayer circuit board. The leads of the multilayer substrate are bonded to corresponding bonding pads formed on the semiconductor chip. A package body is formed on the multilayer substrate around the semiconductor chip and in the slot of the multilayer substrate. The multilayer substrate is capable of providing a power or ground plane formed therein for enhancing the electrical performance of the package, and providing a high wiring density for packaging a chip with high I/O connections. This invention also provides a method of producing a multilayer substrate for use in forming a lead-bond type chip package

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to a lead-bond type chip package, and morespecifically to a multilayer substrate for use in forming the lead-bondtype chip package. This invention also pertains to a method for makingthe multilayer substrate.

[0003] 2. Description of the Related Art

[0004]FIG. 1 depicts a conventional lead-bond type chip package 100comprising a semiconductor chip 130 disposed on a substrate 120 throughan elastomer pad 110. The semiconductor chip 130 has a plurality ofbonding pads 132 disposed thereon. The substrate 120 includes aplurality of solder pads 122 and leads 124 provided on the upper surfacethereof. The solder pads 122 are electrically connected to correspondingleads 124 through conductive traces on the substrate 120. The substrate120 has a plurality of through-holes corresponding to the solder pads122 such that each of the solder pads 122 has at least a portion exposedfrom its corresponding through-hole for mounting a solder ball 126. Theleads 124 are bonded to corresponding bonding pads 132 therebyelectrically connecting the semiconductor chip 130 to the substrate 120.A package body 140 is formed around the semiconductor chip 130 andfilled the slot 120 a of the substrate 120. The package body 140 isformed from insulating material such as epoxy resin.

[0005] The substrate 120 is typically made from flexible polyimide film;hence, it is prone to be deformed by external forces (e.g. stress due toCTE (coefficient of thermal expansion) mismatch) thereby resulting inproblems of die cracking or delamination. Further, since the substrate120 only has a layer of conductor circuit (i.e. the solder pads 122, theleads 124, and the conductive traces), it is difficult to provide enoughpower and ground planes. Therefore, the conventional lead-bond type chippackage 100 does not provide a good signal plane for current surges intoor out of the semiconductor chip 130. The relatively poor electricalperformance associated with the package 100 is especially apparent whenthe semiconductor chip 130 includes high density, high frequency digitalcircuitry.

[0006] The structures utilized to provide the first level connectionbetween the chip and the substrate must accommodate all of the requiredelectrical interconnections to the chip. The number of connections toexternal circuit elements, commonly referred to as “input-output” or“I/O” connections, is determined by the structure and function of thechip. Advanced chips capable of performing numerous functions mayrequire substantial number of I/O connections. Therefore, it willpossibly happen that some of the I/O connections of a chip can not belead-bonded for electrical connection due to the insufficiency of wiringdensity in the substrate with a single layer of conductor circuit. Ifthis were the case, multiple layer structure will be required for thechip with high I/O connections.

[0007] The present invention therefore seeks to provide a lead-bond typechip package which overcomes, or at least reduces the above-mentionedproblems of the prior art.

SUMMARY OF THE INVENTION

[0008] It is a primary object of the present invention to provide alead-bond type chip package comprising a multilayer substrate capable ofproviding enough power and ground planes thereby enhancing theelectrical performance of the package.

[0009] It is another object of the present invention to provide alead-bond type chip package comprising a multilayer substrate withenhanced mechanical strength thereby reducing problems of die crackingor delamination.

[0010] Accordingly, in a first aspect, the present invention provides alead-bond type chip package including a multilayer substrate forsupporting and electrical interconnecting a semiconductor chip. Themultilayer substrate has a slot defined therein. The multilayersubstrate comprises an interlayer circuit board having a dielectriclayer formed thereon, a plurality of leads on the dielectric layer onthe upper surface of the interlayer circuit board, and a plurality ofsolder pads for making external electrical connection disposed on thedielectric layer on the lower surface of the interlayer circuit board.The solder pads are electrically connected to corresponding leads. Theinterlayer circuit board has conductor circuits formed therein. Theleads of the multilayer substrate are bonded to corresponding bondingpads formed on the semiconductor chip. A package body is formed on themultilayer substrate around the semiconductor chip and in the slot ofthe multilayer substrate.

[0011] Preferably, the interlayer circuit board is formed from a corelayer made of fiberglass reinforced BT (bismaleimide-triazine) resin orFR-4 fiberglass reinforced epoxy resin thereby increasing the mechanicalstrength of the multilayer substrate. The interlayer circuit boardcomprises at least a ground plane (or a power plane) formed therein forenhancing the electrical performance of the lead-bond type chip package.Moreover, the dielectric layer on the interlayer circuit board ispreferably formed from prepreg which comprises a semi-curedthermosetting resin as well as glass fibers dispersed therein wherebythe mechanical strength of the multilayer substrate is furtherincreased.

[0012] According to a second aspect, this invention further provides amethod of producing a multilayer substrate for use in forming alead-bond type chip package comprising the steps of:

[0013] (a) providing an interlayer circuit board in which conductorcircuits have been formed, the interlayer circuit board having adielectric layer formed thereon and a slot defined therein; (b)providing a first copper foil with one surface coated by aetch-resistant layer; (c) laminating on one surface of the interlayercircuit board the first copper foil, and the other surface of theinterlayer circuit board a second copper foil in a manner that theetch-resistant coated surface of the first copper foil is in contactwith the dielectric layer on the interlayer plate; (d) selectivelyetching the copper foils laminated on the interlayer circuit board so asto form fine holes at predetermined positions thereof; (e) applyinglaser beams to the prepreg exposed from the fine holes of the copperfoils so as to form via holes and expose parts of the conductor circuitsof the interlayer circuit board; (f) forming through-holes; (g) platinga metal layer to electrically connect the conductor circuits of theinterlayer circuit board and the copper foils; (h) selectively etchingthe first copper foil and the plated metal layer thereon to form aplurality of leads adapted for electrically connecting to asemiconductor chip wherein each of the leads has at least a portionacross the slot of the interlayer circuit board, and selectively etchingthe second copper foil and the plated metal layer thereon to form apredetermined configuration and expose the slot of the interlayercircuit board; (i) stripping the etch-resistant coated on the firstcopper foil exposed within the slot of the interlayer circuit board; (j)forming a solder mask on the patterned surfaces of the multilayersubstrate in a manner that areas on the leads for electricallyconnecting to a semiconductor chip and solder pads for making externalelectrical connection are exposed from the solder mask; and (k) forminga metal coating on the solder pads and the exposed portions of theleads.

[0014] In a preferred embodiment, the step of (a), (b), and (c)described above can be replaced by (a′) providing an interlayer circuitboard in which conductor circuits have been formed, the interlayercircuit board having a slot defined therein; (b′) providing a firstcopper foil with one surface coated by a etch-resistant layer; and (c′)laminating on one surface of the interlayer circuit board the firstcopper foil, and the other surface of the interlayer circuit board asecond copper foil via a plurality of prepregs wherein theetch-resistant coated surface of the first copper foil is in contactwith one of the prepreg, and each prepreg has a slot corresponding tothe slot of the interlayer circuit board.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Other objects, advantages, and novel features of the inventionwill become more apparent from the following detailed description whentaken in conjunction with the accompanying drawings.

[0016]FIG. 1 is a cross-sectional view of a conventional lead-bond typechip package;

[0017] FIGS. 2-8 illustrate a method of making a multilayer substratefor use in forming a lead-bond type chip package in accordance with afirst embodiment of the present invention; and

[0018]FIG. 9 is a cross-sectional view of a portion of a lead-bond typechip package according to a first embodiment of the present invention;

[0019] FIGS. 10-16 illustrate a method of making a multilayer substratefor use in forming a lead-bond type chip package in accordance with asecond embodiment of the present invention; and

[0020]FIG. 17 is a cross-sectional view of a portion of a lead-bond typechip package according to a second embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0021]FIG. 9 discloses a partial portion of a lead-bond type chippackage 200 in accordance with a first embodiment of the presentinvention. The chip package 200 comprises a multilayer substrate 210 forsupporting and electrical interconnecting a semiconductor chip 220. Themultilayer substrate 210 mainly comprises an interlayer circuit board212, a dielectric layer 212 a on the interlayer circuit board 212, aplurality of leads 214 on the dielectric layer 212 a on the uppersurface of the interlayer circuit board 212, and a plurality of solderpads 216 for making external electrical connection disposed on thedielectric layer 212 a on the lower surface of the interlayer circuitboard 212. The solder pads 216 are electrically connected tocorresponding leads 214. The interlayer circuit board 212 has conductorcircuits formed therein. The multilayer substrate 210 has a slot 218defined therein. The leads 214 of the multilayer substrate are directlybonded to corresponding bonding pads 220 a formed on the semiconductorchip 220. A package body 224 is formed on the multilayer substrate 210around the semiconductor chip 220 (not shown) and in the slot 218 of themultilayer substrate 210. Each of the solder pads 216 is provided with asolder ball 217.

[0022] Preferably, the multilayer substrate 210 comprises a solder mask219 formed thereon wherein areas on the leads 214 for electricallyconnecting to the semiconductor chip 220 and the solder pads 216 areexposed from the solder mask 219. And the solder pads 216 and theexposed portions of the leads 214 are provided with a metal coating (notshown) formed thereon. The metal coating on the leads 214 allows a goodbond to be formed with the bonding pads 220 a of the semiconductor chip220. The metal coating typically comprises a layer of nickel coveringthe solder pads 216 and the exposed portions of the leads 214, and alayer of gold (or palladium) covering the nickel layer. The metalcoating prevents the solder pads 216 from corrosion and contaminationthereby assuring the solder joint reliability thereof.

[0023] The lead-bond type chip package 200 is mounted onto a substratesuch as a printed circuit board through the solder balls 217 thatelectrically interconnect the package 200 and the substrate. Preferably,the interlayer circuit board 212 comprises at least a ground plane or apower plane (not shown) formed therein. Therefore, the source voltageand ground potential can be supplied in any desired positions throughthe ground plane and the power plane, so it is possible to shorten thesource voltage or ground potential feed lines to suppress power sourcenoises and attain speed-up of the operation of the chip.

[0024] FIGS. 2-8 show a method of making a multilayer substrate for usein forming the lead-bond type chip package 200 of the present invention.

[0025]FIG. 2 illustrates the interlayer circuit board 212 with adielectric layer 212 a formed thereon. Though only four layers ofconductor circuits of the interlayer circuit board 212 are shown in thispreferred embodiment, a interlayer circuit board for use with theinvention can include any number of layers of conductor circuits ifdesired. The slot 218 can be formed by any of a number of well-knowntechniques including mechanical drilling or laser drilling. Preferably,the interlayer circuit board 212 can be formed by any of a number ofbuild-up technologies. And the interlayer circuit board 212 is formedfrom a core layer 212 b made of fiberglass reinforced BT(bismaleimide-triazine) resin or FR-4 fiberglass reinforced epoxy resinthereby increasing the mechanical strength of the multilayer substrate.Alternatively, the interlayer circuit board 212 may be a multi-layerceramic substrate.

[0026] Referring to FIG. 3, a copper foil 230 with one surface coated bya etch-resistant layer 230 a and a copper foil 240 are laminated on theinterlayer circuit board 212 by conventional methods such asthermocompression. It is noted that the etch-resistant coated surface ofthe copper foil 230 is in contact with the dielectric layer 212 a on theinterlayer circuit board 212.

[0027] Referring to FIG. 4, a photoresist layer 250 is formed over thesurface of the copper foils 230, 240 laminated in the interlayer circuitboard 212 using conventional techniques and materials, then imaged anddeveloped. As is well-known, a photomask is used to image only certainarea of the photoresist layer which, when developed, are removed toleave predetermined portions of the coppers foil 230, 240 exposed. Thenthe exposed portions of the copper foils 230, 240 are etched so as toform fine holes at predetermined positions thereof.

[0028] Referring to FIG. 5, the remaining photoresist is removed andlaser beams are applied to the dielectric layer 212 a exposed from thefine holes of the copper foils 230, 240. The laser beams is used toremove the exposed dielectric layer 212 a until parts of the conductorcircuits of the interlayer circuit board 212 are exposed thereby formingvia holes. Subsequently, through-holes are formed by means of mechanicaldrilling or laser drilling (for simplicity, only one through-hole isshown).

[0029] The types of laser usable in this step include carbon dioxidelaser, YAG laser, excimer laser, etc., of which carbon dioxide laser ispreferred in view of productivity.

[0030] Referring to FIG. 6, a metal layer such as a copper layer 260 isplated for electrically connecting the conductor circuits of theinterlayer circuit board 212 to the copper foils 230, 240. Plating inthis step is carried out by using the same technique as usually employedfor through-hole plating of printed circuit boards, e.g., electrolesscopper plating. The copper layer 260 establishes electrical connectionsbetween the copper foils 230, 240, via holes, through-holes-and theconductor circuits of the interlayer circuit board 212.

[0031] Referring to FIG. 7, the copper foils 230, 240 and the copperlayer 260 thereon are selectively etched to form outer layer circuits byusing conventional techniques described above. It is noted that leads214 adapted for electrically connecting to a semiconductor chip are alsoformed in this step wherein each of the leads 214 has at least a portionacross the slot 218. The purpose of the etch-resistant layer 230 a is toprevent the backside surfaces of leads 214 across the slot 218 frometching in this step. Further, the copper foil 240 and copper layer 260thereon are selectively etched to expose the slot 218 from the bottom ofthe multilayer substrate.

[0032] Referring to FIG. 8, the etch-resistant 230 a on the copper foil230 exposed within the slot 218 is stripped, and then a solder mask 219such as photoimagable solder mask or dry film solder mask is formed overthe patterned surfaces of the multilayer substrate, then imaged anddeveloped. A photomask is used to image only certain area of the soldermask which, when developed, are removed to leave predetermined areasexposed, e.g., areas on the leads 214 for electrically connecting to asemiconductor chip and solder pads 216 for making external electricalconnection.

[0033] Then, a metal coating (not shown) is formed on the exposed areason the solder pads 216 and the exposed portions of the leads 214 byusing conventional plating techniques. Since the metal coating is alsoformed on the leads 214 for electrical connecting to the chip 220, themetal coating should be formed of materials that allow a good bond tothe conventional bonding wire. Preferably, the metal coating comprises alayer of nickel covering the solder pads 216 and the exposed portions ofthe leads 214, and a layer of gold (or palladium) covering the nickellayer.

[0034] Referring to FIG. 9 again, the semiconductor chip 220 is attachedonto the multilayer substrate 210 through an elastomer pad 222. Then abonding tool moves one end of each lead 214 down to the bonding pad 220a on the semiconductor chip 220 and bonds the lead 214 thermosonically.Finally, a package body 224 is formed on the multilayer substrate 210around the semiconductor chip 220 (not shown) and in the slot 218 of themultilayer substrate 210 by using a dipsensing system.

[0035]FIG. 17 discloses a portion of a lead-bond type chip package 300in accordance with a second embodiment of the present invention. Thechip package 300 is substantially identical to the chip package 200 ofFIG. 9 with exception that the prepregs 212 b are used in place of thedielectric layer 212 a on the interlayer circuit board.

[0036] FIGS. 10-16 show a method of making a multilayer substrate foruse in forming the lead-bond type chip package 300 of the presentinvention.

[0037] Referring to FIG. 10, the interlayer circuit board 212, a pairsof prepregs 212 b having slots defined therein, a copper foil 230 withone surface coated by a etch-resistant layer 230 a, and a copper foil240 are illustrated. Though only two layers of conductor circuits of theinterlayer circuit board 212 are shown in this preferred embodiment, ainterlayer circuit board for use with the invention can include anynumber of layers of conductor circuits if desired. The slot 218 can beformed by any of a number of well-known techniques including mechanicaldrilling or laser drilling. The prepregs 212 b comprise a semi-curedthermosetting resin (B-stage condition) as well as glass fibersdispersed therein whereby the mechanical strength of the multilayersubstrate is further increased.

[0038] Referring to FIG. 11, the copper foil 230 and the copper foil 240are laminated on the interlayer circuit board 212 via the prepregs 212 bby conventional methods such as thermocompression. It is noted that theetch-resistant coated surface of the copper foil 230 is in contact withthe one of the prepreg 212 b, and the slot of each prepreg 212 b iscorresponding to the slot 218 of the interlayer circuit board.

[0039] Referring to FIG. 12, a photoresist layer 250 is formed over thesurface of the copper foils 230, 240 using conventional techniques andmaterials, then imaged and developed. Then the exposed portions of thecopper foils 230, 240 are etched so as to form fine holes atpredetermined positions thereof.

[0040] Referring to FIG. 13, the remaining photoresist is removed andlaser beams are applied to the prepreg 212 b exposed from the fine holesof the copper foils 230, 240. The laser beams is used to remove theexposed prepreg 212 b until parts of the conductor circuits of theinterlayer circuit board 212 are exposed thereby forming via holes.Subsequently, through-holes are formed by means of mechanical drillingor laser drilling (for simplicity, only one through-hole is shown).

[0041] Referring to FIG. 14, a metal layer such as a copper layer 260 isplated for electrically connecting the conductor circuits of theinterlayer circuit board 212 to the copper foils 230, 240.

[0042] Referring to FIG. 15, the copper foils 230, 240 and the copperlayer 260 thereon are selectively etched to form outer layer circuits byusing conventional techniques described above. It is noted that leads214 adapted for electrically connecting to a semiconductor chip are alsoformed in this step wherein each of the leads 214 has at least a portionacross the slot 218. Further, the copper foil 240 and copper layer 260are selectively etched to expose the slot 218 from the bottom of themultilayer substrate.

[0043] Referring to FIG. 16, the etch-resistant 230 a on the copper foil230 exposed within the slot 218 is stripped, and then a solder mask 219such as photoimagable solder mask or dry film solder mask is formed overthe patterned surfaces of the multilayer substrate, then imaged anddeveloped.

[0044] Then, a metal coating (not shown) is formed on the exposed areason the solder pads 216 and the exposed portions of the leads 214 byusing conventional plating techniques.

[0045] Referring to FIG. 17 again, the semiconductor chip 220 isattached onto the multilayer substrate 210 through an elastomer pad 222.Then a bonding tool moves one end of each lead 214 down to the bondingpad 220 a on the semiconductor chip 220 and bonds the lead 214thermosonically. Finally, a package body 224 is formed on the multilayersubstrate 210 around the semiconductor chip 220 (not shown) and in theslot 218 of the multilayer substrate 210 by using a dipsensing system.

[0046] The present invention provides a novel multilayer substrateadapted for use in forming a lead-bond type chip package. The multilayersubstrate is capable of providing a closer power or ground plane than isprovided by the underlying system PCB (printed circuit board) power orground plane. The presence of this closer power or ground plane enhancesthe electrical performance of the lead-bond type chip package. Themultilayer substrate also can provide a high wiring density forpackaging a chip with high I/O connections. Moreover, the mechanicalstrength of the multilayer substrate can be further increased by theprepregs disposed therein, since each prepreg comprises glass fibersimpregnated with thermosetting resin.

[0047] Although the invention has been explained in relation to itspreferred embodiment, it is to be understood that many other possiblemodifications and variations can be made without departing from thespirit and scope of the invention as hereinafter claimed.

What is claimed is:
 1. A method of making a multilayer substrate for usein forming a lead-bond type chip package comprising the steps of:providing an interlayer circuit board in which conductor circuits havebeen formed, the interlayer circuit board having a dielectric layerformed thereon and a slot defined therein; providing a first copper foilwith one surface coated by a etch-resistant layer; laminating on onesurface of the interlayer circuit board the first copper foil, and theother surface of the interlayer circuit board a second copper foil in amanner that the etch-resistant coated surface of the first copper foilis in contact with the dielectric layer on the interlayer plate;selectively etching the copper foils laminated on the interlayer circuitboard so as to form fine holes at predetermined positions thereof;applying laser beams to the dielectric layer of the interlayer circuitboard exposed from the fine holes of the copper foils so as to form viaholes and expose parts of the conductor circuits of the interlayercircuit board; forming through-holes; plating a metal layer toelectrically connect the conductor circuits of the interlayer circuitboard and the copper foils; selectively etching the first copper foiland the plated metal layer thereon to form a plurality of leads adaptedfor electrically connecting to a semiconductor chip wherein each of theleads has at least a portion across the slot of the interlayer circuitboard, and selectively etching the second copper foil and the platedmetal layer thereon to form a predetermined configuration and expose theslot of the interlayer circuit board; stripping the etch-resistant onthe first copper foil exposed within the slot of the interlayer circuitboard; forming a solder mask on the patterned surfaces of the multilayersubstrate in a manner that areas on the leads for electricallyconnecting to a semiconductor chip and solder pads for making externalelectrical connection are exposed from the solder mask; and forming ametal coating on the solder pads and the exposed portions of the leads.2. The method as claimed in claim 1, wherein the interlayer circuitboard further comprises a ground plane for supplying ground potential.3. The method as claimed in claim 1, wherein the interlayer circuitboard further comprises a power plane for supplying the source voltage.4. The method as claimed in claim 1, wherein the interlayer circuitboard is formed from fiberglass reinforced BT (bismaleimide-triazine)resin.
 5. The method as claimed in claim 1, wherein the interlayercircuit board is formed from FR-4 fiberglass reinforced epoxy resin. 6.The method as claimed in claim 1, wherein the interlayer circuit boardis formed from ceramic materials.
 7. The method as claimed in claim 1,wherein the metal coating comprises a layer of nickel covering thesolder pads and the exposed portions of the leads, and a layer of metalselected from the group consisted of gold and palladium covering thenickel layer.
 8. A method of making a multilayer substrate for use informing a lead-bond type chip package comprising the steps of: providingan interlayer circuit board in which conductor circuits have beenformed, the interlayer circuit board having a slot defined therein;providing a first copper foil with one surface coated by aetch-resistant layer; laminating on one surface of the interlayercircuit board the first copper foil, and the other surface of theinterlayer circuit board a second copper foil via a plurality ofprepregs wherein the etch-resistant coated surface of the first copperfoil is in contact with one of the prepreg, and each prepreg has a slotcorresponding to the slot of the interlayer circuit board; selectivelyetching the copper foils laminated on the interlayer circuit board so asto form fine holes at predetermined positions thereof; applying laserbeams to the prepreg exposed from the fine holes of the copper foils soas to form via holes and expose parts of the conductor circuits of theinterlayer circuit board; forming through-holes; plating a metal layerto electrically connect the conductor circuits of the interlayer circuitboard and the copper foils; selectively etching the first copper foiland the plated metal layer thereon to form a plurality of leads adaptedfor electrically connecting to a semiconductor chip wherein each of theleads has at least a portion across the slot of the interlayer circuitboard, and selectively etching the second copper foil and the platedmetal layer thereon to form a predetermined configuration and expose theslot of the interlayer circuit board; stripping the etch-resistant onthe first copper foil exposed within the slot of the interlayer circuitboard; forming a solder mask on the patterned surfaces of the multilayersubstrate in a manner that areas on the leads for electricallyconnecting to a semiconductor chip and solder pads for making externalelectrical connection are exposed from the solder mask; and forming ametal coating on the solder pads and the exposed portions of the leads.9. The method as claimed in claim 8, wherein the interlayer circuitboard further comprises a ground plane for supplying ground potential.10. The method as claimed in claim 8, wherein the interlayer circuitboard further comprises a power plane for supplying the source voltage.11. The method as claimed in claim 8, wherein the interlayer circuitboard is formed from fiberglass reinforced BT (bismaleimide-triazine)resin.
 12. The method as claimed in claim 8, wherein the interlayercircuit board is formed from FR-4 fiberglass reinforced epoxy resin. 13.The method as claimed in claim 8, wherein the interlayer circuit boardis formed from ceramic materials.
 14. The method as claimed in claim 8,wherein the metal coating comprises a layer of nickel covering thesolder pads and the exposed portions of the leads, and a layer of metalselected from the group consisted of gold and palladium covering thenickel layer.
 15. A multilayer substrate for use in forming a lead-bondtype chip package, wherein the multilayer substrate comprising: aninterlayer circuit board having opposing upper and lower surfaces inwhich conductor circuits have been formed, the interlayer circuit boardhaving a dielectric layer formed thereon and a slot defined therein; aplurality of leads on the dielectric layer on the upper surface of theinterlayer circuit board wherein the leads are adapted for electricallyconnecting to a semiconductor chip, and each of the leads has at least aportion across the slot of the interlayer circuit board; a plurality ofsolder pads for making external electrical connection disposed on thedielectric layer on the lower surface of the interlayer circuit board,wherein the solder pads are electrically connected to correspondingleads; a solder mask on the surface of the multilayer substrate whereinareas on the leads for electrically connecting to a semiconductor chipand the solder pads are exposed from the solder mask; and a metalcoating on the solder pads and the exposed portions of the leads. 16.The multilayer substrate as claimed in claim 15, wherein the dielectriclayer on the interlayer circuit board is formed from prepreg.
 17. Themultilayer substrate as claimed in claim 15, further comprising a groundplane for supplying ground potential.
 18. The multilayer substrate asclaimed in claim 15, further comprising a power plane for supplying thesource voltage.
 19. The multilayer substrate as claimed in claim 15,wherein the interlayer circuit board is formed from fiberglassreinforced BT (bismaleimide-triazine) resin.
 20. The multilayersubstrate as claimed in claim 15, wherein the interlayer circuit boardis formed from FR-4 fiberglass reinforced epoxy resin.
 21. Themultilayer substrate as claimed in claim 15, wherein the interlayercircuit board is formed from ceramic materials.
 22. The multilayersubstrate as claimed in claim 15, wherein the metal coating comprises alayer of nickel covering the solder pads and the exposed portions of theleads, and a layer of metal selected from the group consisted of goldand palladium covering the nickel layer.
 23. A lead-bond type chippackage comprising: a multilayer substrate having a slot definedtherein, the multilayer substrate comprising an interlayer circuit boardhaving opposing upper and lower surfaces in which conductor circuitshave been formed, a dielectric layer on the interlayer circuit board, aplurality of leads on the dielectric layer on the upper surface of theinterlayer circuit board, and a plurality of solder pads for makingexternal electrical connection disposed on the dielectric layer on thelower surface of the interlayer circuit board, wherein the solder padsare electrically connected to corresponding leads; a semiconductor chipdisposed on the multilayer substrate, the semiconductor chip having aplurality of bonding pads electrically connected to corresponding leadsof the multilayer substrate; and a package body formed on the multilayersubstrate around the semiconductor chip and in the slot of themultilayer substrate.
 24. The lead-bond type chip package as claimed inclaim 23, wherein the dielectric layer on the interlayer circuit boardis formed from prepreg.
 25. The lead-bond type chip package as claimedin claim 23, wherein the multilayer substrate further comprises a groundplane for supplying ground potential.
 26. The lead-bond type chippackage as claimed in claim 23, wherein the multilayer substrate furthercomprises a power plane for supplying the source voltage.
 27. Thelead-bond type chip package as claimed in claim 23, further comprising aplurality of solder balls disposed on the solder pads of the multilayersubstrate.
 28. The lead-bond type chip package as claimed in claim 23,wherein the multilayer substrate further comprises a solder mask on thesurface thereof wherein areas on the leads for electrically connectingto the semiconductor chip and the solder pads are exposed from thesolder mask, and a metal coating on the solder pads and the exposedportions of the leads.
 29. The lead-bond type chip package as claimed inclaim 28, wherein the metal coating comprises a layer of nickel coveringthe solder pads and the exposed portions of the leads, and a layer ofmetal selected from the group consisted of gold and palladium coveringthe nickel layer.
 30. The lead-bond type chip package as claimed inclaim 23, wherein the interlayer circuit board is formed from fiberglassreinforced BT (bismaleimide-triazine) resin.
 31. The lead-bond type chippackage as claimed in claim 23, wherein the interlayer circuit board isformed from FR-4 fiberglass reinforced epoxy resin.
 32. The lead-bondtype chip package as claimed in claim 23, wherein the interlayer circuitboard is formed from ceramic materials.